Thermostat



Aug. 24 1926.

J. C. GIBSON THERMOSTAT Filed Nov. 17', 1922 Patented Aug. l24,y 1926.

JEFFERSON O. GIBSON, OF CHICAGO, ILLINOIS.

rnnauosfrar.

Application led November 17, 1922. Serial No. 601,642. n

The main objects of this invention are to provide an improved thermostat; to provide an improved construction and arrangement of the electrodes; to provide improved means for shiftably `mounting one of said electrodes for the purpose of making and breaking the electric circuit; to provide improved mechanism forl actuating Asaid means; and o topro'vide a device of thiskind which is particularly 'adapted -for use with a bimetallic band or a pressurecontrolled elementh illustrative embodiment of this invention is shown'in the accompanying drawings,"jin which: "",Fig'ure 1 is a front elevation of a thermos'tatn'constructed in accordance with this inveiition, 'the/cover for the lower end thereof being omitted' for the sake of more clearly y illustrating thef arrangement 'of the elecl0 'trodes and the Yshiftingmechanism therefor. Figure'2is a'. jverticalsectional elevation of the' same taken' on the line 2-2-of Figure -1.

- Figure 3 is an enlarged sectional detail Il illustrating the vmanner-in'vvhichfthe adjust able electrode is mounted on the base plate.

Figure 4 shows a modili'cation of the electrode shifting mechanism for use with a pressure-actuated mechanism, a part of .the housing therefor' being omitted for the sake of more -clearly illustrating the electrode shifting means.` 'l

A' thermostat embodying this invention involves' the use' ofa'pivoted lever armf con- `:i5 nected to a member arranged so as to lbe actuated byl temperature or pressure `changes 'for automatically `Lswinging said arm'to retract or engagey electrodes in a circuit lead'- ing toa control devicefor the heating plant,

40 the connection between said member and being such that the shi-toting of the .fle-ver arm arm iseected rather suddenly", soasjto insure a quick making andbreaking 0f the circuit at said electrodes. 46 l. In the yspecific"embodiment shown'in '.Fig-

4`,lires '1' and 2, the thermostat Vcomprises a base plate 1, upon-,Which'is mounted a lever arm -2, y and connected Yt0 and actuated by a ltemperature-control1ed member 3, so as to 50 cause the relative' shiftinggof electrodes' 4 and 5 forming a part of an electric circuit ile' toa coritrol device for the heating laut.k .A shiftable indicator y(iis arrangeda thermometer 7 s mounted upon the base plate for the urpose of indicating the temperature con itions. t

The base plate 1 ispreferably a metaly castin of a size and shape to provide a suitab e support for the various parts of the thermostat. l

The leverarm 2 ispivotally suspended on the4 base plate l at 8, so as to have "a swinging movement in a plane parallel to that of the base. plate 1. The construction of lever 2`and the suspension thereof on the base plate, -and thearrangement of the electrodes 4 and 5, are such that the lever'arm 2 .is normallyfurged by gravity to engage theelectrodes 4 and 5. J .A slot 95 is formed in the lever arm' 2 near the lower end thereof, through which afpiny 10. on. the base plate 1 extends,y and coacts therewith for limiting. the swinging ymovement' of said arm. The head `of. said pin 10 projects somewhatthrou'gh the, slot 9, as shown in Fig. 2, and as will be referred to. 4

` When the shiftingA ofthe lever larm 2 is to ybe controlled by` temperature l changes,

the member. 3 is in the form of a bimetallic spring of a moreor less conventional type, vthe upper portionof which is looped upon itself, as at 1l,.lwith thev end l2 of the member secured to `the upper 'end of the base plate 1,- either directly, Where lthere is to -be no" adjustment or'` the .tensionof said member,` or to a lever 13, vwhere the tension of the memberiis to be adjustedA vfor causing the shifting of the electrodes to 'takeA place at dilierent temperatures. "The `main bodyV part ott member lbelow the loop 11, arrangedin front of the lever arm 2 and disposed in substantially longitudinal alinem'ent therewith.` The member "3 terminates atits lower end near the lowerend -of the 'lever' arm 2, andisconnected to said lever arm by a helical Yspring 14, the `rupper end of' which is 'hooked intothe end of the memvbei", and the lower end of'which is connected to a pin'l'o, secured near the `terminus of the lever arm '2'.

nec'ted thereto and unconnected tothe lever arm 2 and-the member 3. This rod stien'sl Y short rod 16v-is embraced.v within the spring.14vbut"otherwise'unconlos ible conductor 1.9 to a, binding post on the bese plete l. The rod 1S is supported on insulating washers 2i, set in a` lug 22 formed on the oase plete 1 q the rod being. secured in pince by means of nuts 23, which are screwed up against the insulating washers .21. A flexible. conductor Q is secured to the end of the rod 18 and leads to e suitable source of electricity, as does also another conductor t not shown) connected to the binding post The edjusting indicator 6 comprises a pointer 2 integrally formed on the upper end ou, ie leY 12% which lever is pivoted et 2 to the buse plate 1, so that the shifting of the pointer across the scale 27 draws on the end 12 of the member 3, ss to contract or enlarge the loop 11, and thereby alter the spring tension ot' the mein ber 3 und its consequent sensitiveness to temperature changes. A 'thermometer 7 of the usual form, i f, mounted on the base plate 1, in trent ot' the other parts just described, so :is to be readily visible for the purpose .ot indicating the temperature condition of the room wherein the thermostatis used.

A suitable cap (not shown) is adapted vto be placed upon the lower part of the base plate 1, for the purpose of enclosing the mechanism below the thermometer 7. To this end, the brise plate is provided with an aperture :28 to receive a lug on said cap, and with a spring adapted to yieidingly engaf* the cap and hold it in place.

h modification shown in Figure d, the general arrangement of the parts is more or t es in the modiiicaless tue saine tion shown in Figures 1 and 2, with the ex ception that the arrangement is inverted. In this form the member 3 is a bell crunk lever pivoted at 30, with the upper end of the vertical arm connected to the lever arm 2 by -means of the spring 14. The other crm of the bell crank lever carries a Weight 31 adjustable along the length thereof, for the purpesel ot var-ying the sensitivenessot'the device. The member 3 is actuated by the diaphragm device 32, the stem 33 of which ngages the horizontal arm of the member The operation of the device herein shown and described, is substantially as folloivsz The rod 18, carrying the electrode 5 is first adjusted so that at a temperature below ythe other mounted on said Athat desired in the room in which the device is to be used, the lever arm 2 normally en gages the electrodes 4 and 5, thus closing the circuit leading to the control device for the heating plant. The positionof the parts is shown in Figure l, Where it will be observed thaty the extreme'loiver end of the member 3 is slightly to the right of the longitudinal center lino of the lever arm 2, and the axis of spring 1d is inclined to the longitudinal axis of the member 3 und the longitudinal center line of the lever arm rl'he parts remain in this ,position until the temperature in the room has increased to an extent that the differential expansion of the member 3 causes the lower end thereof to swing to the left across and Well past the longitudinal center line of the lever As the spring 14 is thus shifted so-tln1t its axis crosses the longitudinal cent-er line of the lever arm 2, the resiliency ol the spring urges the arm to open the switch and finally causes the lever erm to suddenly swing to the lett and thereby quickly diseugage the electrodes fl and Gravity supplemented by iriction, as at l0, retards the openn until the thermostat tip reaches a point we past the neutral axis or center line el lever 2 whereupon these retarding influences are suddenly overbalenced and the switch flies open. .The breaking of the circuit stops the control device and checks the operation of the heating plant.

The parts remain in this shifted position until the room temperature decreases Sullicicnt to react upon the member, 3 and cause it to shift back into the position shown in Figure l, whereupon the lever arm 2 is shifted to reengage the electrodes 4 and 5 und again close the circuit.

The operation of the moditication shown in l1`igure d is the same, except that the .shifting the member 3 is accomplished by pressure acting on the diaphragm device 32. .Both forms shown are covered by the claims.

Although but two embodiments of this device have been herein shown and described, it will be understood that still other moditicotions tor accomplishing the same purpose n'iay be developed 21ndnumerous details of the modifications herein shown may filtered or omitted without departing from the sp'irit of the invention, as defined in the 'following claims.

I claim: V

1. A thermostat comprising a base plate,

wlever man pivotednt one end t5 said plete Y to have a limited swinging movement, a stop to limit the swing of said arm a. pair oelectrodes, one carried on said'lever armand latein sition to engage with the electr e on said lever arm, an automatically nctuatcd' member mounted on' said plate and arranged substantially in longitudinal alinement with said lever arm and connected at one end to said plate, and a helical spring connectln the other end of saidmember with sai lever arm at a point remote from its pivotal connection to said plate, said spring being disposed in tension nearly in alinement wit the end of said member said spring having a stiifening rod embraced therein but unconnected to said sp ngfmember or lever arm and said stop beinga'rran ed to frictionally oppose the swing df sai spring and rod. IZ. A thermostat comprising a base plate, a lever arm pivotally suspended on said yplate to have a limited swinging movement in a plane parallel to that of said plate, a pair of electrodes, one carried on said lever arm and the other mounted on said late in position to engage with the electro e on said lever arm said lever arm ybeing nora transversely disposed alsA 1 member arranged on said plate substan.

trtf'lly in longitudinal alinement 4with said lever arm, and connected at one end to said plate remote from said lever arm, a resilient connection between the other end of said member andthe other end of said lever arm and said connection being arranged to fric tionally ride upon said pin upon opening the contactof said electrodes, whereby the o eninis retarded and snap action is assure igned at Chicago this 15th day of Nov.,

JEFFERSON C. GIBSON. 

